The invention concerns a method for hauling conveyor units from a main track to a shunting track in a floor chain haulage system, which shunting track contains a part which is directed diagonally onto the main track which is connected onto the main track at the height of a switch and a shunting part which is directed for example parallel to this main track, according to which method the conveyor units are moved over the main track or the shunting track by means of a driven floor chain and catch elements mounted there upon which can carry along a pin of a conveyor unit to be moved and whereby it is determined by means of the switch whether the conveyor unit goes straight ahead or is hauled on the shunting track.
In order to haul a conveyor unit the switch is put in the required position and the floor chain of the shunting track is moved over a distance. Because the shunting track has only one floor chain, the conveyor units which are already shunted are also moved over the same distance. Without any special measures, the hauled Conveyor units must be moved over such a distance on the Shunting track that they are situated entirely outside the path of the conveyor units which follow the main track straight on. Because the part of the shunting track which is connected onto the main track forms an angle, usually of 45 degrees, with the main track, this distance is relatively large, as a result of which also the distance between the conveyor units which are shunted on the actual shunting part is relatively large and in any case larger than necessary to shunt the conveyor units safely without any risk of colliding.
This implies that the number of conveyor units to be shunted is not optimal for a given length of the shunting track.
In order to remedy this problem somewhat, it is already known to drive the floor chain of the shunting track continuously, but to temporarily disconnect the coupling between the pins of the already shunted conveyor units and the catch elements during the haulage, such that the shunted conveyor units are moved over a shorter distance than the floor chain. However, this method requires complicated and expensive coupling and decoupling mechanisms.
Other solutions to increase the shunting capacity include using two floor chains for the shunting track whereby either the two floor chains are driven separately, which requires two drive devices, or one floor chain is driven directly and the other floor chain indirectly, which requires also a transmission system between the two floor chains apart from a drive.
Consequently, these solutions are expensive.